/*
 * Author: Christian Petry
 * Homepage: www.petry-christian.de
 *
 * License: MIT
 * Copyright (c) 2014 Christian Petry
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
 * and associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute, 
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is 
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or 
 * substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 
 * OTHER DEALINGS IN THE SOFTWARE.
 */


// Ported from Stefan Gustavson's java implementation
// http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
//

var SimplexNoise = function(seed) {
	this.grad3 = [[1,1,0],[-1,1,0],[1,-1,0],[-1,-1,0], 
                  [1,0,1],[-1,0,1],[1,0,-1],[-1,0,-1], 
                  [0,1,1],[0,-1,1],[0,1,-1],[0,-1,-1]]; 

    this.grad4 = [[0,1,1,1], [0,1,1,-1], [0,1,-1,1], [0,1,-1,-1],
	     [0,-1,1,1], [0,-1,1,-1], [0,-1,-1,1], [0,-1,-1,-1],
	     [1,0,1,1], [1,0,1,-1], [1,0,-1,1], [1,0,-1,-1],
	     [-1,0,1,1], [-1,0,1,-1], [-1,0,-1,1], [-1,0,-1,-1],
	     [1,1,0,1], [1,1,0,-1], [1,-1,0,1], [1,-1,0,-1],
	     [-1,1,0,1], [-1,1,0,-1], [-1,-1,0,1], [-1,-1,0,-1],
	     [1,1,1,0], [1,1,-1,0], [1,-1,1,0], [1,-1,-1,0],
	     [-1,1,1,0], [-1,1,-1,0], [-1,-1,1,0], [-1,-1,-1,0]];

	this.p = [];
	
	for (var i=0; i<256; i++) {
		this.p[i] = fastfloor(seed == undefined ? Math.random()*256 : randomSeed(seed++)*256);
	}
  
	// To remove the need for index wrapping, double the permutation table length 
	this.perm = [];
	this.permMod12 = []
	for(var i=0; i<512; i++) {
		var v = this.p[i & 255];
		this.perm[i] = v;
		this.permMod12[i] = v.fastmod(12);
	} 
	
	// Skewing and unskewing factors for 2 dimensions
	this.F2 = 0.5*(Math.sqrt(3.0)-1.0); 
	this.G2 = (3.0-Math.sqrt(3.0))/6.0; 

	// A lookup table to traverse the simplex around a given point in 4D. 
  	// Details can be found where this table is used, in the 4D noise method. 
  	this.simplex = [ 
    [0,1,2,3],[0,1,3,2],[0,0,0,0],[0,2,3,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,2,3,0], 
    [0,2,1,3],[0,0,0,0],[0,3,1,2],[0,3,2,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,3,2,0], 
    [0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0], 
    [1,2,0,3],[0,0,0,0],[1,3,0,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,3,0,1],[2,3,1,0], 
    [1,0,2,3],[1,0,3,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,0,3,1],[0,0,0,0],[2,1,3,0], 
    [0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0], 
    [2,0,1,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,0,1,2],[3,0,2,1],[0,0,0,0],[3,1,2,0], 
    [2,1,0,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,1,0,2],[0,0,0,0],[3,2,0,1],[3,2,1,0]]; 
};

 
 
SimplexNoise.prototype.dot = function(g, x, y) { 
	return g[0]*x + g[1]*y;
};

SimplexNoise.prototype.dot3 = function(g, x, y, z) {
  return g[0]*x + g[1]*y + g[2]*z; 
}

SimplexNoise.prototype.dot4 = function(g, x, y, z, w) {
  return g[0]*x + g[1]*y + g[2]*z + g[3]*w;
};


NoiseTypeEnum = {
    PERLINNOISE : 0,
    FRACTALNOISE : 1,
    TURBULENCE : 2
}


// 2D Multi-octave Simplex noise.
//
// For each octave, a higher frequency/lower amplitude function will be added to the original.
// The higher the persistence [0-1], the more of each succeeding octave will be added.
SimplexNoise.prototype.simplexNoise = function( type, size, octaves, persistence, percentage, scale, x, y ) {
    var total = 0;
    var frequency = 0.25;
    var amplitude = 1;
	var offset = size;
	var power = 1 / frequency;
    // We have to keep track of the largest possible amplitude,
    // because each octave adds more, and we need a value in [-1, 1].
    var maxAmplitude = 0;

	//x = (x+offset);
	//y = (y+offset);
	
    for( var i=0; i < octaves; i++ ) {
		// var noise_v = this.noise(x * frequency, y * frequency);
		var x_0_1 = x / size * frequency;
		var y_0_1 = y / size * frequency;
		var noise_v = this.seamlessNoise(x_0_1, y_0_1, scale, scale, offset);

		//noise_v = Math.min (noise_v, (1-percentage));
	
		if (type == NoiseTypeEnum.PERLINNOISE)
			total += noise_v * amplitude;
		else if (type== NoiseTypeEnum.FRACTALNOISE)
			total += Math.abs(noise_v) * amplitude;
		else if (type== NoiseTypeEnum.TURBULENCE)
			total += Math.abs(noise_v) * amplitude;
 
        frequency *= 2;
        maxAmplitude += amplitude;
        amplitude *= persistence;
    }

	if (type == NoiseTypeEnum.TURBULENCE)
		total = Math.sin((x / scale) + total);
	
	var retnoise = total / maxAmplitude;
	
	
	if (type== NoiseTypeEnum.TURBULENCE)
		retnoise = total;
	
	if (type == NoiseTypeEnum.PERLINNOISE || type == NoiseTypeEnum.TURBULENCE)
		retnoise = Math.max(retnoise + percentage,0) / (1.0 + percentage); // [0, 1.0]
	
	retnoise = Math.pow(retnoise, 1 + 2*(1-percentage));
	
    return retnoise;
}


// x, y are normalized coordinates (in [0..1] space).
// dx, dy are noise scale in x and y axes.
// xyOffset is noise offset (same offset will result in having the same noise).
SimplexNoise.prototype.seamlessNoise = function(x, y, dx, dy, xyoffset){
	var s = x;
    var t = y;

    var nx = xyoffset + Math.cos(s * 2.0 * Math.PI) * dx / (2.0 * Math.PI);
    var ny = xyoffset + Math.cos(t * 2.0 * Math.PI) * dy / (2.0 * Math.PI);
    var nz = xyoffset + Math.sin(s * 2.0 * Math.PI) * dx / (2.0 * Math.PI);
    var nw = xyoffset + Math.sin(t * 2.0 * Math.PI) * dy / (2.0 * Math.PI);

    return this.noise4d(nx, ny, nz, nw);
}


SimplexNoise.prototype.noise = function(xin, yin) { 
	var n0, n1, n2; // Noise contributions from the three corners 
	// Skew the input space to determine which simplex cell we're in 
	
	var s = (xin+yin)*this.F2; // Hairy factor for 2D 
	var i = fastfloor(xin+s); 
	var j = fastfloor(yin+s); 
	
	var t = (i+j)*this.G2; 
	var X0 = i-t; // Unskew the cell origin back to (x,y) space 
	var Y0 = j-t; 
	var x0 = xin-X0; // The x,y distances from the cell origin 
	var y0 = yin-Y0; 
	
	// For the 2D case, the simplex shape is an equilateral triangle. 
	// Determine which simplex we are in. 
	var i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords 
	if(x0>y0)
		{i1=1; j1=0;} // lower triangle, XY order: (0,0)->(1,0)->(1,1) 
	else 
		{i1=0; j1=1;}      // upper triangle, YX order: (0,0)->(0,1)->(1,1) 
	
	// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and 
	// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where 
	// c = (3-sqrt(3))/6 
	var x1 = x0 - i1 + this.G2; // Offsets for middle corner in (x,y) unskewed coords 
	var y1 = y0 - j1 + this.G2; 
	var x2 = x0 - 1.0 + 2.0 * this.G2; // Offsets for last corner in (x,y) unskewed coords 
	var y2 = y0 - 1.0 + 2.0 * this.G2; 
	
	// Work out the hashed gradient indices of the three simplex corners 
	var ii = i & 255; 
	var jj = j & 255; 
	var gi0 = this.permMod12[ii+this.perm[jj]]; 
	var gi1 = this.permMod12[ii+i1+this.perm[jj+j1]];
	var gi2 = this.permMod12[ii+1+this.perm[jj+1]];
	
	// Calculate the contribution from the three corners 
	var t0 = 0.5 - x0*x0-y0*y0; 
	if(t0<0) 
		n0 = 0.0; 
	else { 
		t0 *= t0; 
		n0 = t0 * t0 * this.dot(this.grad3[gi0], x0, y0);  // (x,y) of grad3 used for 2D gradient 
	} 
	var t1 = 0.5 - x1*x1-y1*y1; 
	if(t1<0) 
		n1 = 0.0; 
	else { 
		t1 *= t1; 
		n1 = t1 * t1 * this.dot(this.grad3[gi1], x1, y1); 
	}
	var t2 = 0.5 - x2*x2-y2*y2; 
	if(t2<0) 
		n2 = 0.0; 
	else { 
		t2 *= t2; 
		n2 = t2 * t2 * this.dot(this.grad3[gi2], x2, y2); 
	} 
	
	// Add contributions from each corner to get the final noise value. 
	// The result is scaled to return values in the interval [-1,1]. 
	
	var r = 70.0 * (n0 + n1 + n2);
	//r = (r + 1) / 2; //interval [0,1]. 
	return r;
};

// 4D simplex noise
SimplexNoise.prototype.noise4d = function( x, y, z, w ) {
	// For faster and easier lookups
	var grad4 = this.grad4;
	var simplex = this.simplex;
	var perm = this.perm;
	
   // The skewing and unskewing factors are hairy again for the 4D case
   var F4 = (Math.sqrt(5.0)-1.0)/4.0;
   var G4 = (5.0-Math.sqrt(5.0))/20.0;
   var n0, n1, n2, n3, n4; // Noise contributions from the five corners
   // Skew the (x,y,z,w) space to determine which cell of 24 simplices we're in
   var s = (x + y + z + w) * F4; // Factor for 4D skewing
   var i = Math.floor(x + s);
   var j = Math.floor(y + s);
   var k = Math.floor(z + s);
   var l = Math.floor(w + s);
   var t = (i + j + k + l) * G4; // Factor for 4D unskewing
   var X0 = i - t; // Unskew the cell origin back to (x,y,z,w) space
   var Y0 = j - t;
   var Z0 = k - t;
   var W0 = l - t;
   var x0 = x - X0;  // The x,y,z,w distances from the cell origin
   var y0 = y - Y0;
   var z0 = z - Z0;
   var w0 = w - W0;

   // For the 4D case, the simplex is a 4D shape I won't even try to describe.
   // To find out which of the 24 possible simplices we're in, we need to
   // determine the magnitude ordering of x0, y0, z0 and w0.
   // The method below is a good way of finding the ordering of x,y,z,w and
   // then find the correct traversal order for the simplex we’re in.
   // First, six pair-wise comparisons are performed between each possible pair
   // of the four coordinates, and the results are used to add up binary bits
   // for an integer index.
   var c1 = (x0 > y0) ? 32 : 0;
   var c2 = (x0 > z0) ? 16 : 0;
   var c3 = (y0 > z0) ? 8 : 0;
   var c4 = (x0 > w0) ? 4 : 0;
   var c5 = (y0 > w0) ? 2 : 0;
   var c6 = (z0 > w0) ? 1 : 0;
   var c = c1 + c2 + c3 + c4 + c5 + c6;
   var i1, j1, k1, l1; // The integer offsets for the second simplex corner
   var i2, j2, k2, l2; // The integer offsets for the third simplex corner
   var i3, j3, k3, l3; // The integer offsets for the fourth simplex corner
   // simplex[c] is a 4-vector with the numbers 0, 1, 2 and 3 in some order.
   // Many values of c will never occur, since e.g. x>y>z>w makes x<z, y<w and x<w
   // impossible. Only the 24 indices which have non-zero entries make any sense.
   // We use a thresholding to set the coordinates in turn from the largest magnitude.
   // The number 3 in the "simplex" array is at the position of the largest coordinate.
   i1 = simplex[c][0]>=3 ? 1 : 0;
   j1 = simplex[c][1]>=3 ? 1 : 0;
   k1 = simplex[c][2]>=3 ? 1 : 0;
   l1 = simplex[c][3]>=3 ? 1 : 0;
   // The number 2 in the "simplex" array is at the second largest coordinate.
   i2 = simplex[c][0]>=2 ? 1 : 0;
   j2 = simplex[c][1]>=2 ? 1 : 0;    k2 = simplex[c][2]>=2 ? 1 : 0;
   l2 = simplex[c][3]>=2 ? 1 : 0;
   // The number 1 in the "simplex" array is at the second smallest coordinate.
   i3 = simplex[c][0]>=1 ? 1 : 0;
   j3 = simplex[c][1]>=1 ? 1 : 0;
   k3 = simplex[c][2]>=1 ? 1 : 0;
   l3 = simplex[c][3]>=1 ? 1 : 0;
   // The fifth corner has all coordinate offsets = 1, so no need to look that up.
   var x1 = x0 - i1 + G4; // Offsets for second corner in (x,y,z,w) coords
   var y1 = y0 - j1 + G4;
   var z1 = z0 - k1 + G4;
   var w1 = w0 - l1 + G4;
   var x2 = x0 - i2 + 2.0*G4; // Offsets for third corner in (x,y,z,w) coords
   var y2 = y0 - j2 + 2.0*G4;
   var z2 = z0 - k2 + 2.0*G4;
   var w2 = w0 - l2 + 2.0*G4;
   var x3 = x0 - i3 + 3.0*G4; // Offsets for fourth corner in (x,y,z,w) coords
   var y3 = y0 - j3 + 3.0*G4;
   var z3 = z0 - k3 + 3.0*G4;
   var w3 = w0 - l3 + 3.0*G4;
   var x4 = x0 - 1.0 + 4.0*G4; // Offsets for last corner in (x,y,z,w) coords
   var y4 = y0 - 1.0 + 4.0*G4;
   var z4 = z0 - 1.0 + 4.0*G4;
   var w4 = w0 - 1.0 + 4.0*G4;
   // Work out the hashed gradient indices of the five simplex corners
   var ii = i & 255;
   var jj = j & 255;
   var kk = k & 255;
   var ll = l & 255;
   var gi0 = perm[ii+perm[jj+perm[kk+perm[ll]]]] % 32;
   var gi1 = perm[ii+i1+perm[jj+j1+perm[kk+k1+perm[ll+l1]]]] % 32;
   var gi2 = perm[ii+i2+perm[jj+j2+perm[kk+k2+perm[ll+l2]]]] % 32;
   var gi3 = perm[ii+i3+perm[jj+j3+perm[kk+k3+perm[ll+l3]]]] % 32;
   var gi4 = perm[ii+1+perm[jj+1+perm[kk+1+perm[ll+1]]]] % 32;
   // Calculate the contribution from the five corners
   var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0 - w0*w0;
   if(t0<0) n0 = 0.0;
   else {
     t0 *= t0;
     n0 = t0 * t0 * this.dot4(grad4[gi0], x0, y0, z0, w0);
   }
  var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1 - w1*w1;
   if(t1<0) n1 = 0.0;
   else {
     t1 *= t1;
     n1 = t1 * t1 * this.dot4(grad4[gi1], x1, y1, z1, w1);
   }
  var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2 - w2*w2;
   if(t2<0) n2 = 0.0;
   else {
     t2 *= t2;
     n2 = t2 * t2 * this.dot4(grad4[gi2], x2, y2, z2, w2);
   }   var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3 - w3*w3;
   if(t3<0) n3 = 0.0;
   else {
     t3 *= t3;
     n3 = t3 * t3 * this.dot4(grad4[gi3], x3, y3, z3, w3);
   }
  var t4 = 0.6 - x4*x4 - y4*y4 - z4*z4 - w4*w4;
   if(t4<0) n4 = 0.0;
   else {
     t4 *= t4;
     n4 = t4 * t4 * this.dot4(grad4[gi4], x4, y4, z4, w4);
   }
   // Sum up and scale the result to cover the range [-1,1]
   return 27.0 * (n0 + n1 + n2 + n3 + n4);
};